Apparatus for cleaning contaminants from substrate

ABSTRACT

A substrate holder is defined to support a substrate. A rotating mechanism is defined to rotate the substrate holder. An applicator is defined to extend over the substrate holder to dispense a cleaning material onto a surface of the substrate when present on the substrate holder. The applicator is defined to apply a downward force to the cleaning material on the surface of the substrate. In one embodiment the cleaning material is gelatinous.

CLAIM OF PRIORITY

This application is a Divisional application of U.S. patent applicationSer. No. 11/519,354, filed on Sep. 11, 2006, now U.S. Pat. No.7,799,141, entitled “Method and System for Using a Two-Phases SubstrateCleaning Compound,” which 1) claims the benefit of U.S. ProvisionalPatent Application No. 60/755,377, filed on Dec. 30, 2005, and 2) is aContinuation-In-Part of U.S. patent application Ser. No. 10/608,871,filed on Jun. 27, 2003 now abandoned. The disclosure of eachabove-identified patent application is incorporated in its entiretyherein by reference.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to the following U.S. Patent Applications:

-   -   U.S. patent application Ser. No. 12/862,072, filed on Aug. 24,        2010, and entitled “Two-Phase Substrate Cleaning Material;”    -   U.S. patent application Ser. No. 10/816,337, filed on Mar. 31,        2004, and entitled “Apparatuses and Methods for Cleaning a        Substrate,” now U.S. Pat. No. 7,441,299;    -   U.S. patent application Ser. No. 11/173,132, filed on Jun. 30,        2005, and entitled “System and Method for Producing Bubble Free        Liquids for Nanometer Scale Semiconductor Processing,” now U.S.        Pat. No. 7,452,408;    -   U.S. patent application Ser. No. 11/153,957, filed on Jun. 15,        2005, and entitled “Method and Apparatus for Cleaning a        Substrate Using Non-Newtonian Fluids;”    -   U.S. patent application Ser. No. 11/154,129, filed on Jun. 15,        2005, and entitled “Method and Apparatus for Transporting a        Substrate Using Non-Newtonian Fluid,” now U.S. Pat. No.        7,416,370;    -   U.S. patent application Ser. No. 11/174,080, filed on Jun. 30,        2005, and entitled “Method for Removing Material from        Semiconductor Wafer and Apparatus for Performing the Same;”    -   U.S. patent application Ser. No. 10/746,114, filed on Dec. 23,        2003, and entitled “Method and Apparatus for Cleaning        Semiconductor Wafers using Compressed and/or Pressurized Foams,        Bubbles, and/or Liquids,” now U.S. Pat. No. 7,568,490; and    -   U.S. patent application Ser. No. 11/336,215 filed on Jan. 20,        2006, and entitled “Method and Apparatus for Removing        Contamination from Substrate,” now U.S. Pat. No. 7,648,584.

The disclosure of each above-identified patent application isincorporated in its entirety herein by reference.

BACKGROUND OF THE INVENTION

In the fabrication of semiconductor devices such as integrated circuits,memory cells, and the like, a series of manufacturing operations areperformed to define features on semiconductor substrates (“substrates”).During the series of manufacturing operations, the substrate surface isexposed to various types of contaminants. Essentially any materialpresent in a manufacturing operation is a potential source ofcontamination. For example, sources of contamination may include processgases, chemicals, deposition materials, etch by-products, and liquids,among others. The various contaminants may deposit on the wafer surfacein particulate form (particles).

The surface of semiconductor substrates must be cleaned of substratecontaminants. If not removed, the devices within the vicinity of thecontamination will likely be inoperable. Substrate contaminants may alsoaffect device performance characteristics and cause device failure tooccur at faster rates than usual. Thus, it is necessary to cleancontaminants from the substrate surface in a substantially completemanner without damaging the substrate surface and the features definedon the substrate. The size of particulate contamination is often on theorder of the critical dimension size of features fabricated on thewafer. Removal of such small particulate contamination without adverselyaffecting the surface and features on the substrate can be quitedifficult.

In view of the foregoing, there is a need for an improved substratecleaning technique to remove contaminants from substrate surface toimprove device yield.

BRIEF SUMMARY OF THE INVENTION

Broadly speaking, the embodiments fill the need by providing improvedsubstrate cleaning techniques to remove contaminants from the substratesurface to improve device yield. It should be appreciated that thepresent invention can be implemented in numerous ways, including as asolution, a method, a process, an apparatus, or a system. Severalinventive embodiments of the present invention are described below.

In one embodiment, a cleaning compound to remove particulatecontaminants from a semiconductor substrate surface is provided. Thecleaning compound includes a viscous liquid with a viscosity betweenabout 1 cP to about 10,000 cP. The cleaning compound also includes aplurality of solid components dispersed in the viscous liquid, theplurality of solid components interact with the particulate contaminantson the substrate surface to remove the particulate contaminants from thesubstrate surface.

In another embodiment, an apparatus for cleaning particulatecontaminants from a substrate surface of a substrate is provided. Theapparatus includes a substrate support assembly for holding thesubstrate. The apparatus also includes an applicator to dispense acleaning compound to clean the particulate contaminants from thesubstrate surface, wherein the cleaning compound is a viscous liquidhaving a viscosity between about 1 cP to about 10,000 cP at the shearrate of 1 per second and a plurality of solid components are dispersedin the viscous liquid.

In yet another embodiment, a method to clean particulate contaminantsfrom a substrate surface is provided. The method includes applying aviscous liquid having solid components dispersed therein to thesubstrate surface. The method also includes applying a force having adown-ward component and a shear component to the viscous liquid to bringat least one solid component within proximity of a particulatecontaminant on the substrate surface. The method further includesremoving the at least one solid component and the particulatecontaminant away from the substrate surface.

In one embodiment, an apparatus is disclosed for cleaning particulatecontaminants from a semiconductor substrate surface. The apparatusincludes a substrate holder defined to support a substrate. Theapparatus also includes a rotating mechanism defined to rotate thesubstrate holder. The apparatus further includes an applicator definedto extend over the substrate holder to dispense a cleaning material ontoa surface of the substrate when present on the substrate holder. Theapplicator is defined to apply a downward force to the cleaning materialon the surface of the substrate.

In one embodiment, an apparatus is disclosed for cleaning particulatecontaminants from a semiconductor substrate surface. The apparatusincludes a substrate holder defined to support a substrate. Theapparatus also includes a rotating mechanism defined to rotate thesubstrate holder. The apparatus further includes an applicator definedto extend over the substrate holder to dispense a gelatinous cleaningmaterial through multiple dispense holes onto a surface of the substratewhen present on the substrate holder. The gelatinous cleaning materialis dispensed between the substrate and the applicator. The applicator isdefined to apply a downward force to the gelatinous cleaning material onthe surface of the substrate.

Other aspects and advantages of the invention will become apparent fromthe following detailed description, taken in conjunction with theaccompanying drawings, illustrating by way of example the principles ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a physical diagram of a cleaning solution for removingparticulate contamination from a substrate surface, in accordance withone embodiment of the present invention;

FIG. 1B shows a physical diagram of a cleaning solution with a gel and anetwork of solid compounds;

FIG. 1C shows a diagram of stress and viscosity as a function of shearrate for a non-Newtonian fluid;

FIG. 1D shows a physical diagram of a solid component of the cleaningsolution of FIG. 1A in the proximity of a contaminant on the substratesurface;

FIG. 1E shows a physical diagram of solid component of the cleaningsolution of FIG. 1A making contact with contaminant on the substratesurface;

FIG. 1F shows a physical diagram of solid component of the cleaningsolution of FIG. 1A moving contaminant away from the substrate surface;

FIG. 2 shows an embodiment of a process flow for removing particulatecontaminants from the surface of a substrate; and

FIG. 3 shows a schematic diagram of an embodiment of a substrate surfacecleaning system.

DETAILED DESCRIPTION OF THE INVENTION

Several exemplary embodiments for improved substrate cleaning techniqueto remove particulate contaminants from the substrate to improve processyield are provided. It should be appreciated that the present inventioncan be implemented in numerous ways, including as a solution, a process,a method, an apparatus, or a system. Several inventive embodiments ofthe present invention are described below. It will be apparent to thoseskilled in the art that the present invention may be practiced withoutsome or all of the specific details set forth herein.

The embodiments described herein provide for a cleaning technique thateliminates the need for abrasive contact and is efficient at cleaningcontaminants from semiconductor substrates, some of which may containhigh aspect ratio features. While the embodiments provide specificexamples related to semiconductor cleaning applications, these cleaningapplications may be extended to any technology requiring the removal ofcontaminants from a substrate. As described below, a cleaning solutionhaving a continuous liquid phase and a dispersed solid phase isprovided. Solid particles are dispersed throughout the liquid phase.

FIG. 1A shows a physical diagram of a cleaning solution (or compound)101 for removing contaminants 103 from a surface 106 of a semiconductorsubstrate 105, in accordance with one embodiment of the presentinvention. The cleaning solution 101 includes a viscous liquid 107, andsolid components 109. The solid components 109 are dispersed within theviscous liquid 107. The viscous liquid 107 provides a vehicle to bringthe solid components 109 proximate to the contaminants 103 in order forthe solid components 109 and the contaminants 103 to interact toeventually remove the contaminants 103 from the substrate surface 106.In one embodiment, the solid components 109 are hydrolyzed by a chemicalagent, or by added surfactant. In one embodiment, the cleaning solution101 can be prepared by dissolving a carboxylic acid solid in de-ionizedwater (DIW) with a weight/weight percent greater than 2%. The solidcompounds 109 are carboxylic acid solids precipitated from dissolvedcarboxylic acid in the DIW. In one embodiment, the carbon number of thecarboxylic acid is ≧4. The dissolved carboxylic acid would form aviscous liquid 107 with a viscosity between 1 cP (centi-Poise) to about10,000 cP at the shear rate of 1 per second. One thing to note is thatthe cleaning compound (or solution) can be made by mixing carboxylicacid(s) (or salts) in solvents other than water. Other polar ornon-polar solvents, such as alcohol, can also be used.

The solid components 109 are dispersed in suspension within the viscousliquid 107. In one embodiment, the viscous liquid 107 is a gel thatcombines with a network of solid components 109 to form the cleaningcompound 101, which can be applied on the substrate surface 106, asshown in FIG. 1B. The solid components 109 interact with one another toform the network of solid compound through van der Waals forces. Thesolid components 109 are suspended within the viscous liquid 107, whichis in the form of a gel. The relatively high viscosity of the gel allowsa force applied on the gel to transmit the force on the solid compoundin the gel. The cleaning compound 101, as shown in FIG. 1B, can beformed by mixing higher concentration of the carboxylic acid solids,such as between about 3% to about 5% and preferably between about 4% toabout 5%, with DIW. In one embodiment, the mixture of carboxylic acidsolids and DIW can be heated to about 75° C. to about 85° C. to shortenthe duration for the solids to be dissolved in DIW. Once the solids aredissolved, the cleaning solution can be cooled down. During the coolingdown process, solid compounds in the form of needles or plates wouldprecipitates.

In one embodiment, the viscous liquid 107 is a non-Newtonian fluid whoseviscosity decreases with the increase of shear rate. However, theviscous fluid 107 can be a Newtonian fluid. FIG. 1C shows a diagram of anon-Newtonian fluid of the described embodiment. The viscosityapproaches zero when the shear rate is very high. The viscosity of thenon-Newtonian fluid decreases as the shear rate increases. During thecleaning operation, a certain range of shear rate is selected. As anexample, a liquid gel with 3-4 weight/weight % carboxylic acid in DIWhas a viscosity of about 1000 cP at 0.1 per second shear rate and theviscosity falls to about 10 cP when the shear rate increases to 1000 persecond.

As described above, the viscous liquid 107 has a viscosity between about10 cP to about 10,000 cp. When a shear force is applied on a surface ofthe solution 101, the viscous liquid 107 can transfer part of the shearforce to the solid compounds 109. The solid compounds 109 would contactcontaminants 103 and move the contaminants away from the substratesurface.

It should be understood that depending on the particular embodiment, thesolid components 109 within the cleaning material 101 may possessphysical properties representing essentially any sub-state within thesolid phase, wherein the solid phase is defined as a phase other thanliquid or gas. For example, physical properties such as elasticity andplasticity can vary among different types of solid components 109 withinthe cleaning material 101. Additionally, it should be understood that invarious embodiments the solid components 109 can be defined ascrystalline solids or non-crystalline solids. Regardless of theirparticular physical properties, the solid components 109 within thecleaning material 101 should be capable of avoiding adherence to thesurface of substrate surface 106 when positioned in either closeproximity to or in contact with the substrate surface 106. Additionally,the mechanical properties of the solid components 109 should not causedamage to the substrate surface 106 during the cleaning process. In oneembodiment, the hardness of the solid components 109 is less than thehardness of the substrate surface 106.

Furthermore, the solid components 109 should be capable of establishingan interaction with the contaminants 103 present on the substratesurface 106 when positioned in either close proximity or contact withthe contaminants 103. For example, the size and shape of the solidcomponents 109 should be favorable for establishing the interactionbetween the solid components 109 and the contaminants 103. In oneembodiment, the solid compounds 109 have cross-sectional areas greaterthan the cross-sectional areas of the contaminants. As shown in FIG. 1D,when a solid compound 109′ with a large surface area A_(109′) comparedto the surface area A_(103′) of a particulate contaminant 103′, theshear force F_(S′) exerted on the solid compound 109′ is transmittedupon the particulate contaminant 103′ at a shear force multipliedroughly by the area ratio (F_(S)′×A_(109′)/A_(103′)). For example, theeffective diameter D of the particulate contaminant 103′ is less thanabout 0.1 micron. The width W and length L of the solid compound 109′are both between about 5 micron to about 50 micron and the thickness ofthe solid compound 109′ is between about 1 micron to about 5 micron. Thearea ratio (or force multiplier) could be between 2,500 to about 250,000or greater. The shear force exerted on the particulate contaminant 103′could be very large and could dislodge particulate contaminant 103′ fromthe substrate surface 106.

Energy transferred from the solid component 109′ to the contaminant 103′can occur through direct or indirect contact and may cause thecontaminant 103′ to be dislodged from the substrate surface 106. In thisembodiment, the solid component 109′ may be softer or harder than thecontaminant 103′. If the solid component 109′ is softer than thecontaminant 103′, greater deformation of the solid component 109′ islikely to occur during the collision, resulting in less transfer ofkinetic energy for dislodging the contaminant 103′ from the substratesurface 106. In the case where the solid component 109′ is softer thanthe contaminant 103′, the adhesive connection between the solidcomponent 109′ and the contaminant 103′ may be stronger. Conversely, ifthe solid component 109′ is at least as hard as the contaminant 103′, asubstantially complete transfer of energy can occur between the solidcomponent 109′ and the contaminant 103′, thus increasing the force thatserves to dislodge the contaminant 103′ from the substrate surface 106.However, in the case where the solid component 109′ is at least as hardas the contaminant 103′, interaction forces that rely on deformation ofthe solid component 109′ may be reduced. It should be appreciated thatphysical properties and relative velocities associated with the solidcomponent 109′ and the contaminant 103′ will influence the collisioninteraction there between.

FIGS. 1E and 1F show another embodiment of how the cleaning material 101functions to remove the contaminant 103 from the substrate surface 106.During the cleaning process a downward force F_(D), which is a downwardcomponent of force F, is exerted on the solid components 109 within theviscous liquid 107 such that the solid components 109 are brought withinclose proximity or contact with the contaminants 103 on the substratesurface 106. The relatively high viscosity of the viscous liquid 107enables a significant portion of the downward force applied on theviscous liquid 107 to be exerted on the solid components 109. When thesolid component 109 is forced within sufficient proximity to or contactwith the contaminant 103, an interaction is established between thesolid component 109 and the contaminant 103. The interaction between thesolid component 109 and the contaminant 103 is sufficient to overcome anadhesive force between the contaminant 103 and the substrate surface106, as well as any repulsive forces between the solid component 109 andthe contaminant. Therefore, when the solid component 109 is moved awayfrom the substrate surface 106 by a sheer force F_(S), which is a shearcomponent for force F, the contaminant 103 that interacted with thesolid component 109 is also moved away from the substrate surface 106,i.e., the contaminant 103 is cleaned from the substrate surface 106. Inone embodiment, the interaction between the solid component 109 andcontaminant 103 occurs when the solid component 109 is forcedsufficiently close to the contaminant 103. In one embodiment, thisdistance may be within about 10 nanometers. In another embodiment, theinteraction between the solid component 109 and contaminant 103 occurswhen the solid component 109 actually contacts the contaminant 103. Thisinteraction may also be referred to as solid component 109 engagingcontaminant 103.

The interaction force between the solid component 109 and thecontaminant 103 is stronger than the force connecting the contaminant103 to the substrate surface 106. FIG. 1F, shows when a solid component109 is moved away from the substrate surface 106, the contaminant 103bound to the solid component 109 is also moved away from the substratesurface 106. It should be noted that multiple contaminant removalmechanisms can occur during the cleaning process.

It should be appreciated that because the solid components 109 interactwith the contamination 103 to affect the cleaning process, contamination103 removal across the substrate surface 106 will be dependent on howwell the solid components 109 are distributed across the substratesurface 106. In a preferred embodiment, the solid components 109 will beso well distributed that essentially every contaminant 103 on thesubstrate surface 106 will be in proximity to at least one solidcomponent 109. It should also be appreciated that one solid component109 may come in contact with or interact with more than one contaminant103, either in a simultaneous manner or in a sequential manner.Furthermore, solid component 109 may be a mixture of differentcomponents as opposed to all the same component. Thus, the cleaningsolution is capable of being designed for a specific purpose, i.e.,targeting a specific contaminant, or the cleaning solution can have abroad spectrum of contaminant targets where multiple solid componentsare provided.

Interaction between the solid component 109 and the contaminant 103 canbe established through one or more mechanisms including adhesion,collision, and attractive forces, among others. Adhesion between thesolid component 109 and contaminant 103 can be established throughchemical interaction and/or physical interaction. For example, in oneembodiment, chemical interaction causes a glue-like effect to occurbetween the solid component 109 and the contaminant 103. In anotherembodiment, physical interaction between the solid component 109 and thecontaminant 103 is facilitated by the mechanical properties of the solidcomponent 109. For example, the solid component 109 can be malleablesuch that when pressed against the contaminant 103, the contaminant 103becomes imprinted within the malleable solid component 109, In anotherembodiment, the contaminant 103 can become entangled in a network ofsolid components 109. In this embodiment, mechanical stresses can betransferred through the network of solid components 109 to thecontaminant 103, thus providing the mechanical force necessary forremoval of the contaminant 103 from the substrate surface 106.

Deformation of the solid component 109 due to imprinting by thecontaminant 103 creates a mechanical linkage between the solid component109 and the contaminant 103. For example, a surface topography of thecontaminant 103 may be such that as the contaminant 103 is pressed intothe solid component 109, portions of the solid component 109 materialenters regions within the surface topography of the contaminant 103 fromwhich the solid component 109 material cannot easily escape, therebycreating a locking mechanism.

In addition to the foregoing, in one embodiment, interaction between thesolid component 109 and contaminant 103 can result from electrostaticattraction. For example, if the solid component 109 and the contaminant103 have opposite surface charges they will be electrically attracted toeach other. It is possible that the electrostatic attraction between thesolid component 109 and the contaminant 103 can be sufficient toovercome the force connecting the contaminant 103 to the substratesurface 106.

In another embodiment, an electrostatic repulsion may exist between thesolid component 109 and the contaminant 103. For example, both the solidcomponent 109 and the contaminant 103 can have either a negative surfacecharge or a positive surface charge. If the solid component 109 and thecontaminant 103 can be brought into close enough proximity, theelectrostatic repulsion there between can be overcome through van derWaals attraction. The force applied by the viscous liquid 107 to thesolid component 109 may be sufficient to overcome the electrostaticrepulsion such that van der Waals attractive forces are establishedbetween the solid component 109 and the contaminant 103.

Additionally, in another embodiment, the pH of the viscous liquid 107can be adjusted to compensate for surface charges present on one or bothof the solid component 109 and contaminant 103, such that theelectrostatic repulsion there between is reduced to facilitateinteraction, or so that either the solid component or the contaminationexhibit surface charge reversal relative to the other resulting inelectrostatic attraction. For example, a base, such as AmmoniumHydroxide (NH₄OH), can be added to a carboxylic acid gel, made bydissolving 3-4% of a carboxylic acid in DIW, with fatty acid solidcomponents to increase the pH value of the gel (viscous liquid). Theamount of NH₄OH added is between about 0.05% to about 5%, preferablybetween about 0.25% to about 2%. Ammonium Hydroxide helps the fatty acidsolids to be hydrolyzed and to be dispersed in the gel. AmmoniumHydroxide can also hydrolyze the contaminants 103. To clean metalcontaminants, lower pH solution can also be used. Buffered HF solutioncan be used to tune the pH value to be between about 6 to about 8.

In addition to using a base, such as Ammonium Hydroxide, to enhancecleaning efficiency, a surfactant, such as ammonium dodecyl sulfate,CH₃(CH₂)₁₁OSO₃NH₄, can also be added to the carboxylic acid gel. In oneembodiment, about 0.1% to about 5% of surfactant is added to thecleaning solution 101. In a preferred embodiment, about 0.5% to about 2%surfactant is added to the cleaning solution 101.

In addition, the solid components 109 should avoid dissolution or havinglimited solubility in the viscous liquid 107, and should have a surfacefunctionality that enables dispersion throughout the viscous liquid 107.For solid components 109 that do not have surface functionality thatenables dispersion throughout the liquid medium 107, chemicaldispersants may be added to the liquid medium 107 to enable dispersionof the solid components 109. Depending on their specific chemicalcharacteristics and their interaction with the surrounding viscousliquid 107, solid components 109 may take one or more of severaldifferent forms. For example, in various embodiments the solidcomponents 109 may form aggregates, colloids, gels, coalesced spheres,or essentially any other type of agglutination, coagulation,flocculation, agglomeration, or coalescence. In other embodiments, thesolid components 109 may take a form not specifically identified herein.Therefore, the point to understand is that the solid components 109 canbe defined as essentially any solid material capable of functioning inthe manner previously described with respect to their interaction withthe substrate surface 106 and the contaminants 103.

Some exemplary solid components 109 include aliphatic acids, carboxylicacids, paraffin, cellulose, wax, polymers, polystyrene, polypeptides,and other visco-elastic materials. The solid component 109 materialshould be present at a concentration that exceeds its solubility limitwithin the viscous liquid 107. In addition, it should be understood thatthe cleaning effectiveness associated with a particular solid component109 material may vary as a function of temperature, pH, and otherenvironmental conditions.

The aliphatic acids represent essentially any acid defined by organiccompounds in which carbon atoms form open chains. A fatty acid is anexample of an aliphatic acid and an example of a carboxylic acid thatcan be used as the solid components 109 within the cleaning material101. Examples of fatty acids that may be used as the solid components109 include lauric, palmitic, stearic, oleic, linoleic, linolenic,arachidonic, gadoleic, eurcic, butyric, caproic, caprylic, myristic,margaric, behenic, lignoseric, myristoleic, palmitoleic, nervanic,parinaric, timnodonic, brassic, clupanodonic acid, lignoceric acid,cerotic acid, and mixtures thereof, among others. In one embodiment, thesolid components 109 can represent a mixture of fatty acids defined byvarious carbon chain lengths extending from C4 to about C-26. Carboxylicacids are defined by essentially any organic acid that includes one ormore carboxyl groups (COOH). Also, the carboxylic acids can includeother functional groups such as but not limited to methyl, vinyl,alkyne, amide, primary amine, secondary amine, tertiary amine, azo,nitrile, nitro, nitroso, pyrifyl, carboxyl, peroxy, aldehyde, ketone,primary imine, secondary imine, ether, ester, halogen isocyanate,isothiocyanate, phenyl, benzyl, phosphodiester, sulfhydryl, but stillmaintaining insolubility in the viscous liquid 107.

Additionally, the surface functionality of the solid component 109materials can be influenced by the inclusion of moieties that aremiscible with the viscous liquid 107, such as carboxylate, phosphate,sulfate groups, polyol groups, ethylene oxide, etc. The point to beunderstood is that the solid components 109 should be dispersible in asubstantially uniform manner throughout the viscous liquid 107 such thatthe solid components 109 avoid clumping together into a form that cannotbe forced to interact with the contaminants 103 present on the substrate105.

It should be understood that the viscous liquid 107 can be modified toinclude ionic or non-ionic solvents and other chemical additives. Forexample, the chemical additives to the viscous liquid 107 can includeany combination of co-solvents, pH modifiers, chelating agents, polarsolvents, surfactants, ammonium hydroxide, hydrogen peroxide,hydrofluoric acid, tetramethylammonium hydroxide, and rheology modifierssuch as polymers, particulates, and polypeptides.

FIG. 2 is an illustration showing a flowchart of a method for removingcontaminants from a substrate surface, in accordance with one embodimentof the present invention. It should be understood that the substratereferenced in the method of FIG. 2 can represent a semiconductor waferor any other type of substrate from which contaminants associated with afabrication process need to be removed. Also, the contaminantsreferenced in the method of FIG. 2 can represent essentially any type ofsurface contaminant associated with the semiconductor wafer fabricationprocess, including but not limited to particulate contamination, tracemetal contamination, organic contamination, photoresist debris,contamination from wafer handling equipment, and wafer backsideparticulate contamination.

The method of FIG. 2 includes an operation 201 for disposing a cleaningmaterial (or solution) over a substrate, wherein the cleaning materialincludes solid components dispersed within a viscous liquid, or a gel.The cleaning material referenced in the method of FIG. 2 is the same aspreviously described with respect to FIGS. 1A-1F. Therefore, the solidcomponents within the cleaning material are dispersed in suspensionwithin the viscous liquid. Also, the solid components are defined toavoid damaging the substrate and to avoid adherence to the substratesurface.

The method also includes an operation 203 for applying a force to asolid component to bring the solid component within proximity to acontaminant present on the substrate, such that an interaction isestablished between the solid component and the contaminant.

Additionally, in one embodiment, the method can include an operation forcontrolling a temperature of the cleaning material to enhanceinteraction between the solid component and the contaminant. Morespecifically, the temperature of the cleaning material can be controlledto control the properties of the solid component. For example, at ahigher temperature the solid component may be more malleable such thatit conforms better when pressed against the contaminant. Then, once thesolid component is pressed and conformed to the contaminant, thetemperature is lowered to make the solid component less malleable tobetter hold its conformal shape relative to the contaminant, thuseffectively locking the solid component and contaminant together. Thetemperature may be used to control the viscosity of the viscous liquid.The temperature may also be used to control the solubility and thereforethe concentration of the solid components. For example, at highertemperatures the solid component may be more likely to dissolve in theviscous liquid. The temperature may also be used to control and/orenable formation of solid components in-situ on the substrate fromliquid-liquid suspension. In a separate embodiment, the method caninclude an operation for precipitating solids dissolved within theviscous liquid. This precipitation operation can be accomplished bydissolving the solids into a solvent and then adding a component that ismiscible with the solvent but that does not dissolve the solid.

The method further includes an operation 205 for moving the solidcomponent away from the substrate surface such that the contaminant thatinteracted with the solid component is removed from the substratesurface. In one embodiment, the method includes an operation forcontrolling a flow rate of the cleaning material over the substrate tocontrol or enhance movement of the solid component and/or contaminantaway from the substrate. The method of the present invention forremoving contamination from a substrate can be implemented in manydifferent ways so long as there is a means for applying a force to thesolid components of the cleaning material such that the solid componentsestablish an interaction with the contaminants to be removed.

In one embodiment, the method can include an operation of a final clean.In the operation of final clean, the substrate the cleaning material,that contains dislodged contaminants, is cleaned with a suitablechemical(s) that facilitates the removal of all the cleaning materialfrom the substrate surface. For example, if the viscous liquid of thecleaning material is a carboxylic acid gel, NH₄OH diluted in DIW couldbe used to remove carboxylic acid off the substrate surface. NH₄OHhydrolyzes (or ionizes by deprotonating) the carboxylic acid and enablesthe hydrolyzed carboxylic acid to be lifted off the substrate surface.Alternatively, a surfactant, such as ammonium dodecyl Sulfate,CH₃(CH₂)₁₁OSO₃NH₄, can be added in DIW, to remove carboxylic acid geloff the substrate surface.

In another embodiment, a rinse operation follows the final cleanoperation described above. After the final clean, the substrate surfacecan be rinsed with a liquid, such as DIW, to remove the chemical(s) usedin the final clean from the substrate surface. The liquid used in finalrinse should leave no chemical residue(s) on the substrate surface afterit evaporates.

FIG. 3 shows a schematic diagram of an embodiment of a substrate surfacecleaning system 300, System 300 has a container 307 that houses asubstrate support assembly 304. The substrate support assembly 304 has asubstrate holder 305 that supports a substrate 301. The substratesupport assembly 304 is rotated by a rotating mechanism 310. System 300has a cleaning material dispensing assembly 303 that include a cleaningmaterial applicator 306. In the applicator 306, there are multipledispensing holes 308 that allow the cleaning material to be dispensed onthe surface of substrate 301. With the aid of the rotating mechanism310, the cleaning material 307 covers the entire substrate surface. Inone embodiment, the applicator 306, through the action of dispensing ofthe cleaning material, provides a down-ward force to cleaning materialand to the substrate surface. The cleaning material can be pressed outof the applicator 306 by air pressure or by a mechanical pump. Inanother embodiment, the applicator 306 provides a down-ward force on thecleaning material on the substrate surface by a down-ward mechanicalforce. The rotating mechanism 310 provides a sheer force to the cleaningmaterial and to the substrate surface. In one embodiment, the rotatingmechanism 310 is rotated at a speed between about 1 round per minute(RPM) to about 100 RPM, preferably between about 5 RPM to about 30 RPM.The pressure exerted on the cleaning material (or compound) to push thecleaning material out of the applicator 306 is between about 5 PSI toabout 20 PSI. Alternatively, the applicator 306 can rotates around thecenter of the substrate 301 to provide the shear force.

In one embodiment, system 300 also includes a dispenser 320, which candispense DIW 321 on the substrate surface to clean the substrate surfaceof the cleaning material after the process of contaminant-removal by thecleaning material is completed. In another embodiment, the dispenser 320can dispense a cleaning solution, such as NH₄OH in DIW described above,on the substrate surface to hydrolyze the viscous liquid to enable theviscous liquid to be lifted off the substrate surface. Afterwards, thesame dispenser 320 or a different dispenser (not shown) can dispense DIWto remove the cleaning solution from the substrate surface.

While this invention has been described in terms of several embodiments,it will be appreciated that those skilled in the art upon reading thepreceding specifications and studying the drawings will realize variousalterations, additions, permutations and equivalents thereof. Therefore,it is intended that the present invention includes all such alterations,additions, permutations, and equivalents as fall within the true spiritand scope of the invention. hi the claims, elements and/or steps do notimply any particular order of operation, unless explicitly stated in theclaims.

What is claimed is:
 1. A system for cleaning particulate contaminants from a semiconductor substrate surface, comprising: a cleaning material having a viscous liquid with solid components dispersed therein, wherein the solid components are carboxylic acids having a carbon number greater than or equal to four; a substrate holder defined to support a substrate; a rotating mechanism defined to rotate the substrate holder; an applicator defined to extend over the substrate holder to dispense the cleaning material onto a surface of the substrate when present on the substrate holder, wherein the applicator is defined to apply a downward force to the cleaning material on the surface of the substrate; and a cleaning solution dispenser structurally separate from the applicator, the cleaning solution dispenser oriented to dispense a cleaning solution onto the surface of the substrate when present on the substrate holder, and the cleaning solution dispenser oriented to dispense the cleaning solution at a location away from the applicator.
 2. The system as recited in claim 1, wherein the applicator includes multiple dispense holes defined to dispense the cleaning material onto the surface of the substrate.
 3. The system as recited in claim 2, wherein the applicator is defined to press the cleaning material through the multiple dispense holes at a pressure within a range extending from about 5 pounds per square inch (psi) to about 20 psi.
 4. The system as recited in claim 2, wherein the applicator is defined to utilize air pressure to press the cleaning material through the multiple dispense holes.
 5. The system as recited in claim 2, wherein the applicator is defined to utilize a mechanical pump to press the cleaning material through the multiple dispense holes.
 6. The system as recited in claim 1, wherein the downward force applied by the applicator to the cleaning material on the surface of the substrate is a downward mechanical force.
 7. The system as recited in claim 1, wherein the rotating mechanism is defined to provide a shear force to the cleaning material and to the surface of the substrate.
 8. The system as recited in claim 1, wherein the rotating mechanism is defined to rotate the substrate holder at a rate within a range extending from about 1 revolution per minute (RPM) to about 100 RPM.
 9. The system as recited in claim 1, wherein the rotating mechanism is defined to rotate the substrate holder at a rate within a range extending from about 5 RPM to about 30 RPM.
 10. The system as recited in claim 1, wherein the applicator is defined to rotate around a center of the substrate when supported on the substrate holder.
 11. The system as recited in claim 1, wherein the cleaning solution is defined to hydrolyze the cleaning material.
 12. The system as recited in claim 1, further comprising: a container defined to house the substrate holder.
 13. A system for cleaning particulate contaminants from a semiconductor substrate surface, comprising: a gelatinous cleaning material having a viscous liquid with solid components dispersed therein, wherein the solid components are carboxylic acids having a carbon number greater than or equal to four; a substrate holder defined to support a substrate; a rotating mechanism defined to rotate the substrate holder; an applicator defined to extend over the substrate holder to dispense the gelatinous cleaning material through multiple dispense holes onto a surface of the substrate when present on the substrate holder, whereby the gelatinous cleaning material is dispensed between the substrate and the applicator, and wherein the applicator is defined to apply a downward force to the gelatinous cleaning material on the surface of the substrate; and a cleaning solution dispenser structurally separate from the applicator, the cleaning solution dispenser oriented to dispense a cleaning solution onto the surface of the substrate when present on the substrate holder, and the cleaning solution dispenser oriented to dispense the cleaning solution at a location away from the applicator.
 14. The system as recited in claim 13, wherein a viscosity of the gelatinous cleaning material is within a range extending from about 1 centi-Poise (cP) to about 10,000 cP.
 15. The system as recited in claim 13, wherein a concentration of the carboxylic acid solid components in the viscous liquid exceeds a solubility limit of the carboxylic acid solid components in the viscous liquid, and wherein the carboxylic acid solid components are defined to interact with particulate contaminants on the surface of the substrate to remove the particulate contaminants from the surface of the substrate.
 16. The system as recited in claim 15, wherein the concentration of the carboxylic acid solid components in the liquid is at least 2 percent by weight.
 17. The system as recited in claim 13, wherein the applicator is defined to dispense the gelatinous cleaning material through the multiple dispense holes at a pressure within a range extending from about 5 psi to about 20 psi. 